Tungsten carbide has been used in various structures, such as mechanical parts and metal molds, because of its excellent mechanical characteristics (hardness, strength, toughness, abrasion resistance, and the like). A structure containing tungsten carbide is manufactured, for example, by thermal spraying or sintering. In any of such manufacturing method, a binder metal, such as cobalt, nickel, or iron, is used to bind tungsten carbide crystal grains, since tungsten carbide has a high melting point. However, there have been cases in which such a structure (for example, a micro drill) is broken as a result of a binder metal lump (pool) acting as the origin of fracture of the structure.
Likewise, in a case where tungsten carbide is used for coating a mechanical part, thermal spraying is generally adopted. In such a case, a film (structure) formed on the mechanical part by thermal spraying is porous, and therefore its mechanical strength is low and its corrosion resistance is poor. Furthermore, it is difficult to form a film (structure) having a smooth surface only by thermal spraying. When tungsten carbide is utilized in a micropart having a size on the order of micrometers, such as a micro electro mechanical system (MEMS), or in the coating of a micropart, it is impossible to achieve sufficient precision with such a method as the thermal spraying or sintering. Patent Document 1: Japanese Unexamined Patent Application Publication No. 2004-124129